The aim of this work is to study the influence of the temperature on the ultimatetensile strength (UTS) of composite material which is manufactured from polyester andE-glass (woven roving, chopped strand mat) as a laminate with a constant fiber volumefraction (VF) of 33%. The results showed a little effect of temperature on tensilestrength in the range of room temperature (RT) to 50 oC for laminates reinforced withE-glass (woven roving) [0/90, ±45,0/90], [0/90]3, and [0/90, CSM, 0/90], but forlaminates reinforced with E-glass chopped strand mat (CSM), as [CSM] 3 and [CSM,0/90, CSM], a continuous reduction in strength was observed with increasingtemperature from (RT) to 60 oC. The highest percentage reduction in strength was 23%at 60oC as compared with (RT) for [CSM]3 laminate

: This research include the study of tensile strength for the polymer and the composite materials, we using the epoxy resin as matrix for the reinforced materials that consist of artificial fibers (Kevlar, glass and PVC fibers) also aluminum powder for reinforcing.The slates made of composite materials and hybrid composite materials for both volume fractions 20% and 40% from the reinforced materials, Twenty one slates were made from the composite materials, all these slates were cut into samples with measurement (10x 80mm) in order to execute the tensile strength test for both volume fractions 20% and 40%. The results and laboratory examinations for these samples shows increase in the tensile strength for composite materials when the volume fraction increase from 20% to 40% for reinforced material, the samples from type (EK) have tensile strength is higher than all samples for both volume fraction.

This research studied the effect of liquids on the Engineering properties of the Limestone rocks. The liquids used were: crude oil from Ain Zala, crude oil from Kirkuk, natural ground Water. The Limestone used was brought from Eski Mosul situated at 45 Km north west of Mosul. Both the compressive and tensile tests were conducted on the Limestone rock specimens in the dry and saturated case using;Uniaxial, Triaxial Compression and Bending tests. The tests showed that saturation with any one of the liquids lead to a decrease of both compressive and tensile strength. The greatest decrease occurred when ground water was used to saturate the specimens, and it was also noted that the effect of saturation gave greater percentage of decrease on the compressive than the tensile strength. The study also showed that liquids lead to decrease in cohesion ( c ) and the Friction angle (Φ) obtained from triaxial test. The liquids used for saturation didn't have clear effect on the type and mode of failure on all specimens tested .Keyword: σc:Compressive strength σt: Tensile strength

Abstract This paper studies the tensile strength of steel fibrous concrete, four different percentage of fibers where used to find out the effect of the addition of steel fibers on the tensile strength of concrete using the splitting, flexural, and compressive strength of concrete. Test results from this study and earlier published data were used in a regression analysis to derive empirical equations for tensile strength of SFC. The following relationships were derived; splitting strength and the compressive strength of fiber and normal concrete, the relationship between the flexural and compressive strength of SFC and compressive strength of normal concrete, and the splitting cylinder strength and the flexural strength of SFC. Key Words: Steel fiber concrete, tensile strength.

Background: Denture cleaner solutions are used extensively for the cleaning ofprosthesis both plastic and metallic component .The chemical composition of cleanersolution are virtually important in defining their adverse effect on properties of acrylicpart of prosthesisAims of the study The present study carried out to study the effect of somecleaning solution on tensile strength and indentation hardness of both types of acrylicresin (hot and cold cured) and compare the effect on different types of denturematerials.Materials and methods: Specimens of hot and cold cured acrylic resin wereprepared according to ADA specification for both indentation hardness and tensilestrength test. The specimen were immersed in distilled water for seven days then wereleft in containers containing one of the following denture cleaners, Staradent 1%H202,5%HCL& vinegar solution. Each container contained five specimens of either heatcure or cold cure with one type of denture cleaners and they were left for seven days.Specimens were then tested for indentation hardness and tensile strength test.Results: The results showed that Vinegar solution has an deleterious effect ontensile strength and indentation surface hardness of hot cured acrylic resin ascompared with control while for cold cure all specimens affected by all cleaningsolutions.

This work includes an investigation of the effect and optimization of welding parameters on the tensile strength in the arc metal welding process. The experimental studies were conducted under varying welding currents, wire diameters, and heat input. The settings of welding parameters were determined by using the Taguchi experimental design method. The level of importance of the welding parameters on the tensile strength is determined by using analysis of variance (ANOVA). The optimum welding parameter combination was obtained by using the analysis of signal-to-noise (S/N) ratio. The tensile strength model was formulated based on Analysis of Variance (ANOVA) using Minitab® statistical package. The experimental results confirmed the validity of the used Taguchi method for enhancing the welding performance and optimizing the welding parameters in the arc metal welding process.

Background: Nowadays there is an increasing of the emphasis on aesthetic, dentist have been concerned about providing aesthetics and functional removable partial dentures to their patients and this was make the mission more difficult because of the goal now is achieving optimal aesthetic of the denture - while maintaining retentive, stable, and conservative to the health of supporting tooth and supporting tissue. The traditional use of metal clasp like cobalt-chromium, gold, stainless-steel and titanium hampers esthetics because of its obvious display conflicts with patient’s prosthetic confidentiality. Acetal resin (poly oxy methylene) may be used as alternative denture clasp material. This material was promoted primarily on the basis of its superior esthetic.Material and method: In this study, Acetal resin of Flexite and co-cr alloy of Wirocast companies were used. Four metal models of two premolars and two molars were surveyed to have 0.25mm and 0.5mm undercut depth for each one of the materials. eighty clasps were prepared and tested by testing machine to measure the load required to dislodge Acetal and co-cr clasps of 2mm. thickness (for premolar and molar). Tensile test were utilized for both Acetal resin and co-cr. tensile values will be used in special formula to calculate the amount of deflection.Results: The results of this study revealed that Acetal resin clasp of molar with 0.5mm undercut depth have the higher retentive force, and premolar with 0.25 mm undercut depth have the lowest retentive force as compared to co-cr. Also Acetal had lower values of the tensile strength as compared to co-cr alloy but it had higher deflection value than co-cr and it can withstand higher deflections than those of co-cr before having permanent deformation or fractureConclusions: Acetal resin can be used with limitation as an alternative to co-cr alloy clasps in removable partial dentures.

Degassing technique currently applied to cast aluminum alloys due to its technological and economic advantages. The present work aimed to study the effect of degassing technique of cast aluminum alloy (LM2) under different pressures using squeeze casting process. Inert argon gas was pumped into the molten aluminum with flow rate (2,5-5-7)l/min. at constant pumped duration (5min.). Different applied pressures were used(17, 35, 52) MPa. The test was performed at room temperature. The physical and mechanical properties of degassed samples were measured and compared with non-degassing (ND) samples. The results showed that the best condition of degassing is found at 2.5 l/min flow rate and 35 MPa applied pressure. It was found that a slight difference is observed for the density and the lowest value of porosity was obtained at 2.5 l/min flow rate and 52 MPa applied pressure.

In this research, attempt has been made to understand the effect of tool shape on the strength of aluminum alloy (AA2024-T3). Seven different tool pin profiles (straight cylindrical, threaded cylindrical, tapered cylindrical, threaded taper, triangular, hexagonal and square) with two different shoulder surfaces (flat and concave) that have been used to fabricate the joint. The effect of tool geometry on the strength of welded joints was investigated using different mechanical tests including (tensile, bending and microhardness tests). Also, a non-destructive tests including (visual and liquid penetration tests) were achieved. Microstructural characteristics during friction stir weldingprocess were studied and the welding joints were investigated using optical microscope. The best mechanical properties obtained in this research were observed in the hexagonal pin profile with concave shoulder where the maximum welding efficiencies were (89.4%) and (85.71%) in terms of ultimate tensile strength and bending force respectively. The weakness tensile strength and bending force were found in the straight cylinder pin profile with flat shoulder as compared with the other tool shapes. The hardness values are higher in the weld zone compared to that in base metal. The maximum value of hardness is observed in the nugget zone of welded sample with hexagonal pin and concave shoulder profile. A fine equiaxed grains size is formed along the parent metal grain structure.

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.